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When a circuit breaker trips, it will shut down the air compressor system, and work comes to a halt. When a Craftsman air compressor trips breaker, it’s a worrying issue, as you’ll no longer be able to use your air tools.

Therefore, it is important to understand the reasons why your Craftsman air compressor is tripping breaker, and so, this article will provide you with all the relevant information, along with existing reader questions and responses.

Table of Contents

7 Reasons Your Craftsman Air Compressor Trips Breaker

Here is a list of the 7 most common reasons your Craftsman air compressor is tripping breaker:

  1. The air filter – if they are dirty, you will need to replace it
  2. Broken extension cords – are notorious for throttling power, and therefore you may be underpowering your compressor motor by using one.
  3. Clogged cylinders – can hinder performance and trip breaker. You should inspect the cylinders (if your compressor has any).
  4. Faulty circuit breaker – of course, it could be the circuit breaker that is faulty. Replace if necessary.
  5. Faulty motor – the motor windings or any other electrical connections inside the motor may be shorting and this sudden flow of electricity pulls too many amps, tripping the breaker.
  6. Failed capacitor – a failing capacitor can cause the breaker to trip, you should seek professional help to test this.
  7. Failed unloader valve – When an unloader valve fails, compressed air will become trapped over the cylinder piston and this adds to the load the compressor motor experiences on startup, tripping the breaker.

For more detailed information on why an air compressor circuit breaker trips, visit our guide!

Reader Questions & Responses

Craftsman Air Compressor Trips Breaker – Craftsman Air Compressor Troubleshooting

Question

33 gal. 11.9cfm Craftsman. A.O.smith motor. 115V rpm3450 mod. 919.167340. motor turns slow then trips the breaker, worked fine last time it was used. how many ohms should this motor show on the meter? It’s showing 3.

Response

I don’t have the spec for that, Gary.

If you go to www.searspartsdirect.com and input your model number, you can see the parts diagram and list.

You can also (if during business hours) chat online with them. I would ask if that info was in the manual before I ordered one, or, just if they knew what that was.

What is the pressure in the tank when the “motor turns slow then trips breaker”? On cut in with pressure, or even when the tank is empty?

If no change in the power supply to the compressor, then check the intake filter to make sure it’s clean, pull the line from the pump head to the tank, and see if the compressor runs OK then. If so, apply gloved back pressure to the fitting or port in the pump head to see if this causes the motor to lug. If not, pull and clean the check valve, then try it again.


Craftsman Air Compressor Keeps Tripping Breaker – Troubleshooting Craftsman Air Compressor

Question

Compressor Motor Terminal Wiring

Got this motor to run a hydraulic press. Even when not connected to the press the following happens:

The motor starts up really slow, and the cable (16 amp) starts to heat up from the plug end. If left on for more than a minute, the motor will heat up.

It is a 220v motor single phase.

Was working before being posted to me, it was taken to 2500psi where it stalled the pump.

I am certain the supplier is correct and it was ok before posting.

The plug is connected to a 30amp main fuse in my house. It blew a 13amp fuse before I changed the fuse to 20amp. I am wondering if the problem is the start capacitor/run capacitor or the changeover switch?

I am just using a normal switch, ie no soft start, DOL, etc. My research suggests that this motor should run on a normal 220v household supply, albeit linked to a 16amp + fuse.

Frank

The connection box has four connections, U1, U2, 3, and 4. My life is connected to U1, neutral to U2.


Craftsman Air compressor Trips Breaker and Motor Stops

Question

After I push the reset (red) button, the compressor will run for about 5 seconds and then cut off. The air tank is not full at all of the air.

Response

Sounds like the motor is failing, or you haven’t enough current to the motor to allow it to run properly

The reset button is often a thermal reset. The cut-off occurs when the motor gets too hot, to try and save it from heat-related damage. By repeatedly pushing the thermal reset button, and not addressing the issue that caused it, you are likely doing more damage to the motor.

Make sure nothing else pulls power from the same circuit that feeds your compressor. If, after that, the symptom continues, I’m guessing that your motor is the problem.


Craftsman Compressor Trips Breaker – Troubleshooting Craftsman Compressor

Question

This compressor keeps tripping my garage breaker at start-up! It will start up a second or two then trip the breaker. It ran fine the other day! but I don’t think it ever cut back On when it hit the Cut-in pressure (110)Cut-Out pressure is set at 130?

I remember I was getting low air pressure but I have finished anyway. Now it won’t run without tripping the breaker in a second or two! The regulator seems fine, the pressure switch seems OK, the unloader valve works In/Out before it trips out, Check Valve OK, Safety Valve OK, the motor isn’t binding and the fan turns fine, what do I check next? and where can I get parts? I need some help, please!

Craftsman 919.165200 compressor
Craftsman 919.165200 compressor

Response

Good on you for checking all the things you have. This is the kind of post that helps me help you.

Two more things to check. What’s changed in the circuit? Do you have any other electric equipment pulling current from the same line as the one that feeds the compressor? Make sure not.

From what you are saying, if there is no additional draw on the power supply, you may have a capacitor problem. It holds a boost of power that is used when the motor starts up, as starting electric motors draws much more power than they need when they are running.

If the capacitor is weak or failing, the boost isn’t there for the motor, it tries to start, pulls too many amps for the circuit, and your breaker trips out after a couple of seconds.

If it was me, I’d take my motor and capacitor (usually on the side of the motor) to a motor rebuild shop and have both checked out.


Craftsman Air Compressor Immediately Trips Breaker

Question

3HP GE Motor trips fuse as soon as I flip the switch. I have removed the motor from the tank and all switches. I disconnected both capacitors and connected a cord directly to the hot and ground on the block. (saw video’s on youtube to bypass the start and run capacitors). Fuse still blows instantly. Bad windings??

Response

In my vast (-:) experience with motors, I would say that you have a fault with the ground. Could be windings, could be a wire loose, pretty hard to tell from here.

Maybe you could post again the youtube link for the bypass of the start run capacitors? Folks (me too) would be interested.


Craftsman Air Compressor Keeps Tripping Breaker

Question

hi Bill I have read all the posts and based on what you’ve said there, I think the problem is the unloader valve. before I go and buy new parts I wanted to check with you and be certain that’s the next step.

when the tank is empty the motor fills it up and it shuts off as it should
as I use the air and the pressure in the tank goes down, the motor tries to come back on as it should. That’s when it blows the breaker.

I have to bleed all the air out of the tank and only then will it start up again.

Seems from what you have been saying in the threads that this points to the unloader valve.

If this is correct, is that the part I go to sears and order? “Hi I need an unloader valve for my craftsman compressor”

Thanks for your help, Bill…

Response

Hi Keni. Good on you for reading and figuring out what is likely your air compressor problem.

Double-check and make sure it’s the unloader valve. You will know from reading that page that the unloader is likely operated by your pressure switch.

Dump the air again, close the drain, fire up the compressor, and watch the unloader as the air in the tank gets close to the normal cut-out level.

As the compressor stops, you should see the unloader valve operate, and if you are close enough over the very loud compressor, hear the air dump out of the unloader.

If the unloader valve isn’t operated by the lever from the pressure switch (unless you have an internal unloader, in which case it means a new switch) then maybe it’s the switch and not the unloader.

So check, before you buy.

And yes, if it is the unloader valve itself that is the problem… it may only be crud inside bunging it up, and if you disassemble it, you may bet it working again.


Craftsman Air Compressor Trips Breaker On Startup

Question

My craftsman 5hp 20gallon compressor trips my breaker at start-up? Craftsman 5hp 20gallon compressor tries to start up but trips my 15amp breaker.

It will run a second or two before doing it. The unloader valve seems to be working, it moves in and out while trying to start, turning the regulator to low or max makes no difference, the check valve works in and out, and the motor fan turns the piston without any snags, what could be the problem?

Craftsman 5 HP air compressor
Craftsman 5 HP air compressor

Response

Is this a new condition? What has changed in the power supply? My first check would be to see what else is pulling power from the same supply circuit.

When you say that it runs for a second or two, does it actually pump air, or is the motor trying to start for a second or two, and then the breaker pops? If this is the case, then I would consider your capacitor suspect. It may not be supplying enough boost power to get your motor going, the motor pulls too many amps for the circuit without the capacitor boost, and the breaker pops.

If neither of these is the cause send me a note as a comment on this thread telling me what you have done, and I’ll respond further.

If you haven’t looked at the page about BLOWS BREAKER OR FUSES from the troubleshooting page, I’d suggest that’s a good read.

Question

Please post a follow-up as this motor is nearly $300. I’d like to get this thing running myself without spending anywhere near that. I have narrowed it down to the motor and want to know if you or anyone else has solved and fixed this problem, also how much time and money were spent doing so.

Response

You may wish to check the circuit breaker.  They also get weak.


Craftsman Compressor Blows Breaker

Question

30 gal. Craftsman 919.167310. No air in the tank.

Craftsman 919.167310 air compressor
Craftsman 919.167310 air compressor

Tried different amp sockets of 20 and 30 amp. Does the same thing.

Tried replacing capacitor of the same type (30 mf- 370v). No joy. Compressor does exact same thing with NO capacitor wired in. Turns fine by hand.

Response

Sounds like the centrifugal switch is not closing properly when the motor is stopped.

This happens to explain no difference when there is no capacitor…

Hope that’s it, as otherwise your start winding may be kaput.

Questioner

I took off the backplate to get at the points. They were together when stopped. I filed them clean and restarted the motor. They pulsed when I attempted to start the motor but stayed together. Points did not appear to “open”.
It seems Sears does not sell the centrifugal switch separate nor does it carry this motor any longer.

Response

Bummer.

If we’re certain it only has one capacitor, then it seems the motor is bad – for whatever reason.

If you can get it to a motor shop to bench test it, that would be good, and they’ll probably have a similar motor in stock if you need one.

If that’s not practical, I’m afraid it’s time to go shopping for either a motor or a new compressor.

Response

All may not be lost. It appears as though there are some commonalities among centrifugal switches.

If you Google “buy a centrifugal switch for compressor motor” as I just did, you will find a) lots of info b) sources to obtain them.

Questioner

There is a 136-163 mfd starter cap within the backplate made by Mallory. 220 vac. How close do I need to come to this output for a replacement? Can I go larger if the unit fits within the motor?

Response

The page on this site that talks about sourcing capacitors says “if the new capacitor has the same voltage range, the same microfarad range, and you can attach it to the existing mounting of the motor capacitor on your compressor, you can use it. Even if it’s a different shape, a different color, longer or shorter or bigger around, as long as the voltage and microfarad ratings are the same, it is a suitable capacitor for your compressor motor.”

Response

OK, I had thought this might be a one-cap thing. Since it has two, that means you replaced the run cap, given the values we now know.

136-163 mfd 220V caps are readily available. If you have one on hand that’s larger, with at least a 220v rating, that may well be ok since it’s only in the circuit for a brief time during start-up.

What cap (mfd and v) were you thinking of trying?

Questioner

I searched the net and found a company that sells this exact capacitor for the A.O. Smith motor on this compressor.

I will let you know if this works.


If you have any questions regarding your Craftsman air compressor tripping breaker, please leave a comment below, with a photo if applicable, so that someone can help you!